When building structures or objects made of a plurality of planar elements, it is necessary to have some sort of apparatus to connect the elements. As early as 1921 (U.S. Pat. No. 1,398,852,) and as recently as 2010 (US 20100285718 A1), toy makers have searched for ways to enable children to make temporary play structures and objects by connecting a plurality of planar elements. Some construction toys have used connecting elements that attach one tubular element to another to create a structure or object upon which flexible material can be draped to create a semi-enclosed space (US 20100285718 A1). Other toys have connecting elements that use slots to take advantage of simple physical properties such as friction and, in some cases, compression to connect rigid planar elements (U.S. Pat. Nos. 3,066,436; 3,177,611; 3,477,188; 3,537,706; 4,257,207). Similar solutions have used two-ended connectors or tabs (U.S. Pat. Nos. 1,426,087; 2,708,329; 4,212,130) to connect these rigid planar elements.
Prior art designed to connect rigid planar elements work—to a point. They are sufficient when connecting a first planar element to a second planar element, and then connecting the first planar element to third planar element. The problem arises when connecting a fourth planar element to the second and third planar elements in a grid pattern as you might use when constructing a wall. (See FIG. 2)
Using this prior art to connect the fourth planar elements to the second and third planar elements creates what might be considered the “Problem of the 4th Planar Element.” To use previous art to attach said fourth element as the last unit of 4-piece grid pattern, the user must push the edges of the fourth planar element onto connectors mounted on the edge of the second and third planar elements.
The heart of the problem with previous art is that it is very difficult—if not impossible—to connect this fourth rigid planar element by pushing it in two directions at the same time directly down onto a second planar element and, simultaneously, directly to the side onto a third planar element whose edge is at 90 degrees from the edge of the second element. Harder still is to do so without bending and distorting the edges of the second, third, or fourth elements, and without completely frustrating the child—or the doting parent—trying to create the structure or object.
Previous art, such as U.S. Pat. Nos. 1,426,087 and 3,827,177 include images of structures constructed using connectors, but if you imagine trying to build the structures represented, you will see that such assembly would be very difficult for the reasons stated above. Some prior art, such as U.S. Pat. No. 3,855,748, is more honest: The images included in this patent doesn't ever try to show that larger structures could be assembled using the invention because it simply would not be possible.
The result of these earlier, limited approaches to connecting multiple planer elements is that users are limited to created smaller, less complex, and more static structures or objects. It is impossible to know if the creators of previous art ever watched children try to create structures or objects using their designs. If they had done so, they would have seen that their approaches create a study in frustration. In addition to the frustration, users would find that trying to create structure with these approaches quickly degrades the parts themselves. Furthermore, the structures and objects created with prior art would be difficult to alter or reconfigure without taking the entire structure or object apart and starting from scratch.